How to use a Natural History Museum coupon

The Smithsonian Institution National Museum of Natural History in Washington, D.C., is free, as are all the Smithsonian Institution museums in the nation's capital. You can visit the museum every day of the year except for Dec. 25 from 10 a.m. to 5:30 p.m. On select days, the museum extends its hours to 7:30 p.m. Check its website for more information.